1. Field
The present invention relates generally to wireless charging, and more specifically to devices, systems, and methods related to wireless power chargers.
2. Background
Typically, each battery powered device such as a wireless communication device (e.g., a cell-phone) requires its own charger and power source, which is usually the AC power outlet. This becomes unwieldy when many devices need charging, each requiring its own separate charger.
Approaches are being developed that use over-the-air or wireless power transmission between a transmitter and a receiver coupled to the electronic device to be charged. Wireless power transmission using radio frequency (RF) is one method considered as an un-tethered means for charging the batteries of portable wireless electronic devices. In wireless power transmission, an off-board RF transmitter and antenna radiates RF energy to the device to be charged. The device to be charged has a receive antenna and circuitry that converts the RF power to DC current that can charge the device's battery, or alternatively, can directly power the device. The distance between the transmitting and receiving antenna, at which efficient energy transfer can take place, is a function of the RF frequencies of operation and the antenna sizes. The coupling efficiency may be significantly improved if the antennas are sized and operated at such a frequency that they are physically within the so-called “near-field zone” of each other. This often necessitates that that both antennas operate at frequencies where the antennas are electrically small (e.g., largest dimension <0.1 wavelengths).
Under conditions of wireless power coupling, there may exist a significant amount of power transmitted by the transmitter to be received by the wireless power receiving device. For communication devices their jamming conditions may result from transmitter harmonics, inter-modulation products in the wireless power receiving device, high voltages generated in the wireless power receiving device, communication receiver antenna detuning while receiving wireless power or through baseband coupling in the wireless power receiving device. This energy created by wireless power coupling may cause problems in the receiver such as jamming which may prevent the wireless power receiving device from effectively communicating such as in making or receiving calls, maintaining an existing call, or establishing other communication links.